Projectiles fitted with and electric detonator operated by a generator of the inertia type



Jan. 28, 1964 G. WYSER 3,119,335

PROJECTILES FITTED WITH AND ELECTRIC DETONATOR OPERATED BY A GENERATOR OF THE INERTIA TYPE Filed Feb. 28, 1961 United States Patent PROJECTIUES FITTED WITH AND ELECTRIC DETONATOR OPERATED BY A GENERATOR OF THE INERTIA TYPE Giulio Wyser, Geneva, Switzerland, assignor to Brevets Aero-Mccaniques S.A., Geneva, witzerland, a society of France Filed Feb. 28, 1961, Set. No. 92,243 Claims priority, application Luxembourg Mar. 3, 1969 Claims. (Cl. 1027l .2)

The invention is more especially, but not exclusively concerned with projectiles undergoing, when launched, relatively low accelerations, which is the case, in particular, of rockets and grenades, either self-propelled or not, launched by means of a rifle.

The object of this invention is to provide a projectile of this kind which is better adapted to meet the requirements of practice than those known up to this time, in particular concerning safety in storing and transportation.

The projectile with which the invention is concerned contains an explosive charge provided with a housing into which the detonator can be engaged by a displacement from the rear toward the front, the detonator being movably mounted in the projectile body so as to be able to move, preferably through the action of return means, from an initial position of rest where it is located on the outside of said housing and in which it is kept by holding means frangible under the effect of the acceleration of the projectile upon launching thereof, to a forward position where it is engaged in said housing.

According to the present invention, the generator is rigid with the detonator and forms therewith a sliding unit movable in the projectile body.

Other features of this invention will become apparent in the course of the following description of a preferred embodiment of the invention given with reference to the accompanying drawings in which:

FIG. 1 is a side view with parts cut away and parts in cross section of a grenade made according to the invention, the parts occupying the position they have in the state of rest;

FIG. 2 is a similar view, the parts being shown in the position they occupy immediately after the grenade has been launched;

FIG. 3 is a similar view, the parts being shown in the position they finally occupy some time after the launching of the grenade.

The grenade shown by the drawings comprises at the front a war-head '1 containing an explosive charge 3 and toward the rear a tubular extension 2 for fitting this grenade on a rifle.

The detonator 4 which is to ignite charge 3 is adapted to be engaged by a frontward displacement into a housing 5, preferably provided with a lining, formed in the rear portion of said charge 3 and open at the rear.

In order to prevent an accidental operation of the detonator from causing charge 3 to explode before launching of the projectile and in particular while it is being stored or while it is being handled before its launching, this detonator 4 is movably mounted in the projectile body so as to be able to move, advantageously under the action of return means consisting of a spring 6, from an initial position of rest (FIG. 1) where said detonator is on the outside of housing 5 and in which position it is kept normally by frangible holding means (more explicitly described hereinalfter) capable of breaking under the effect of a suitable acceleration imparted to the projectile, to a front position (FIG. 3) where said detonator 4 is engaged in its housing 5.

The inertia generator 7, illustrated by FIG. 1, is made as follows. It comprises a coil 8 disposed coaxially with the 3,119,335 Patented Jan. 28, 1964 "ice projectile and along the axis of which can move, in the rearward direction, a bar magnet 9 held in forward position, before the projectile is launched, by frangible means such as a rigid wire 10, which permits of transporting the projectile Without risks in case of its being dropped but is sufficiently weak to break under the effect of an axial acceleration greater than a given value (hereinafter called critical acceleration) imparted to generator '7 and directed frontwardly.

According to the present invention, generator 7 and detonator 4 are fixed together, so as to form a single sliding unit mounted in a guiding housing 11 formed in the projectile body between the front part 1 and the rear part 2 of this projectile, the frangible holding means of detonator 4 therefore serving to keep this sliding unit in position of rest in housing 5.

Thus, owing to the fact that detonator 4 and the casing 7 of the generator (which contains the voltage source, for instance a capacitor to be charged by it) form a single unit, it becomes unnecessary to provide flexible or sliding electric connection between different elements of the electrical firing system.

Preferably, as shown, the sliding unit comprising detonator 4 and generator 7 is movable the projectile body by the effect of inertia and against the action of a return spring 6 from the initial position (shown by FIG. 1), in which it is held before launching by frangible means capable of yielding under the effect of the initial acceleration of the projectile, to a rear position (shown by FIG. 2) where said unit is applied against a rear abutment 12 of the projectile body.

When the projectile is launched, the sliding unit 4, 7, before coming into the front position shown by FIG. 3, moves rearwardly in the projectile body where it is struck by the rear abutment 12, which instantaneously transmits its speed to said unit, thus imparting thereto an acceleration much higher than the acceleration undergone by the projectile when it was launched and also higher than the critical acceleration, so that wire 10 is broken.

It follows that the operation of generator '7, which results from the breaking of wire Ill), is much safer than if said generator were subjected merely to the launching acceleration (which would be the case the generator casing was rigid with the projectile body).

It should be noted that this result is obtained without introducing any complication in the structure and merely by taking advantage of the movable mounting of detonator 4.

Of course, the distance between the rear face of the sliding unit in its position of rest and rear abutment 12 and the strength of return spring 6' must be chosen such that the sliding unit is actually struck by abutment 12 after the projectile has been launched.

The holding means for keeping the sliding unit in its forward position of rest comprises a screw 13 carred by said unit and the head of which consists of a frangible disc 14 secured in the hollow plug forming abutment 12 by means of a locking sleeve 15 fixed in said plug.

The operation of the projectile shown by the drawings is as follows:

Before launching, the sliding unit 4-7 is held by screw 13 and disc 14 in the position of FIG. 1. When the projectile is launched, the initial acceleration causes disc 14 to be sheared and said sliding unit 4--7 remains practically stationary' in space, i.e. moves rearwardly with respect to the projectile body (screw 13 sliding in sleeve 15), until abutment 12 strikes the rear end wall of the casing of generator 7 thus imparting thereto a high acceleration which causes wire 10 to be broken, and bar 9 to slide to the rear of coil 8 (position shown by FIG. 2) thus producing the desired electric current to charge the voltage source (capacitor) of the electric firing device.

3 When the sliding unit 4, 7 is struck by the rear abutment 12, the return spring 6, which was previously compressed, pushes said unit toward the front until (FIG. 3) detonator 4 is engaged into its housing 5.

Advantageously, as shown, to facilitate this movement, detonator 4- carries a forward extension 16 of such a length that it is already engaged in a housing 5 when the sliding unit 4, 7 is in its position of rest.

In a general manner, while I have, in the above description, disclosed what I deem to be a practical and efficient embodiment of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. In a projectile, the combination of a rigid body, an explosive charge in said body, an electric detonator for said charge mounted slidable in said body along the line of projectile motion, said explosive charge being provided with a longitudinal recess open at the rear thereof and forming a housing adapted to accommodate said detonator in the front position thereof with respect to said body, an electric genenator of the inertia type connected with said detonator for supplying it with current, said generator having an element mounted rigid with said detonator, the whole of said detonator and said generator element forming a sliding unit in said projectile body, said generator being operative to supply electric current in response to the launching of said projectile, holding means interposed between said sliding unit and said projectile body for releasably keeping said unit in a position of rest with respect to said body where said detonator is located rearwardly of said explosive charge and not engaged in said housing, said holding means being releasable by the launching of the projectile, and means urging said unit frontwardly after launching of the projectile to engage said detonator into said housing after said holding means has been released upon launching of the projectile.

2. In a projectile, the combination of a rigid body, an explosive charge in said body, an electric detonator for said charge mounted slidable in said body along the line of movement of said projectile, said explosive charge being provided with a longitudinal recess open at the rear thereof and forming a housing adapted to accommodate said detonator in the front position thereof, an electric generator of the inertia type connected with said detonator for supplying it with current, said generator comprising a first element and a second element capable, by relative movement with respect to each other, of producing an electric current, said first element being rigid with said detonator, the whole of said first generator element and of said detonator forming a sliding unit movable in said projectile body in a direction parallel to the direction of movement of the projectile, first frangible means carried by said body for yieldably hold-ing said unit in a position of rest with respect to said body where said detonator is rearwardly of said explosive charge and not engaged in said housing, said body having a rigid abutment for said sliding unit rearwardly of said unit in said position of rest thereof, said second generator element being slidable rearwardly with respect to said first generator element along the line of movement of said projectile, second frangible means mounted between said two generator elements for yieldingly opposing rearward displacements of said second element with respect to said first element, and resilient means between said sliding unit and said body urging said unit frontwardly so as to engage said detonator into said housing after said first frangible means has been broken upon launching of the projectile and said sliding unit has been struck by said abutment.

3. A combination according to claim 2 in which said body forms a cylindrical housing having its axis parallel to the direction of movement of the projectile, said first generator element being in the form of a piston slidable in said housing.

4. A combination according to claim 2 in which said abutment is a hollow plug fixed in said body.

5. A combination according to claim 2 in which said abutment is a hollow plug fixed to the rear of said body, said combination further comprising a screw fixed to the rear of said first generator element and extending rearwardly through said plug, said first mentioned frangible means consisting of a frangible disc having its central portion fixed to the rear of said screw and its circular edge fixed to said plug.

References Cited in the file of this patent UNITED STATES PATENTS 1,858,969 Ruhlemann May 17, 1932 2,703,530 McGee Mar. 8, 1955 2,775,941 Plumley Jan. 1, 1957 2,825,863 Krupen Mar. 4, 1958 2,911,914 Wynn et al. Nov. 10, 1959 

1. IN A PROJECTILE, THE COMBINATION OF A RIGID BODY, AN EXPLOSIVE CHARGE IN SAID BODY, AN ELECTRIC DETONATOR FOR SAID CHARGE MOUNTED SLIDABLE IN SAID BODY ALONG THE LINE OF PROJECTILE MOTION, SAID EXPLOSIVE CHARGE BEING PROVIDED WITH A LONGITUDINAL RECESS OPEN AT THE REAR THEREOF AND FORMING A HOUSING ADAPTED TO ACCOMMODATE SAID DETONATOR IN THE FRONT POSITION THEREOF WITH RESPECT TO SAID BODY, AN ELECTRIC GENERATOR OF THE INERTIA TYPE CONNECTED WITH SAID DETONATOR FOR SUPPLYING IT WITH CURRENT, SAID GENERATOR HAVING AN ELEMENT MOUNTED RIGID WITH SAID DETONATOR, THE WHOLE OF SAID DETONATOR AND SAID GENERATOR ELEMENT FORMING A SLIDING UNIT IN SAID PROJECTILE BODY, SAID GENERATOR BEING OPERATIVE TO SUPPLY ELECTRIC CURRENT IN RESPONSE TO THE LAUNCHING OF SAID PROJECTILE, HOLDING MEANS INTERPOSED BETWEEN SAID SLIDING UNIT AND SAID PROJECTILE 